Blasting cap



March 14, 1933.

.1. PlccARD 1,901,469 BLASTING CAP Filed May l2, 1932 jean /TDc'ccaro/ Patented Mai. 14, 1933 UNITED STATES PATENT OFFICE COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE BLA'STIN G CAP Applicationled May 12, 1932. Serial No. 610,758.

This invention relates to an improvement 1n blasting caps such as are used 1n Viiring commercial explosives. The .improved I blasting cap in accordance with this inven- 5 tion may be of any type, such as a plain cap adapted for firing with a fuse, an electric cap, a delay cap, ete., etc.

As is well known, where la blasting cap fails to tire, it will be present in blasted down material 'and due to its high power will be a distinct menace in the subsequent use of the material. More particularly, an unfired cap presents a very distinct menace where presentl in coal and is likely, if not certain, to cause substantial damage, if not personal injury when the coal is used.

Now it is the object of this invention to provide a blasting cap so constructedthat if it should fail to fire, for example, in connection with the mining-ot` coal, its explosive charge will be destroyed or rendered innocuous in treatment of the coal prior to shipment to the consumer.

Generally speaking the cap in accordance with this invention, which may be of any type, will be provided with a casing adapted to contain any usual charge, as, for'e'xample, an explosive or detonating charge, with or without lan igniter charge, and the casing will be provided with an opening or openings normally closed by means oi a closure 'of any-suitable water soluble material.

In operation if the cap` should fail to fire and remain unred in, for example, coal, it will be destroyed or rendered harmless in the subsequent treatment of the coal for market, as by washing, flotation, jigging, etc., since the water used will dissolve the water soluble closure for the aperture in the casing and the water gaining access to the explosive charge within the casing will wash it out through the opening or openings to be carried away from the coal, or at least -so distributed as to render it harmless.

.Havingnow indicated ina general way the nature and purpose of this invention, I will proceed to a detailed description of preferred embodiments thereofwith reference to the accompanying drawing in which Figure 1 is a perspective view of an electric blasting cap embodying this invention.

Figure 2 is a sectional view of the blasting cap shown in Figure l.

Figure 3 is a perspective view of a blasting cap for fuse ring.

Figure 4f is a sectional view of the cap shown in Figure 3.

In the several figures a indicates any usual blasting cap casing or shell as, for example, the usual copper casing, though as will be appreciated the casing may be made of any desired suitable material and of any desired suitable shape and size without departing from this invention. l.

The casing a is essentially provided with one or more openings in its body, as for example, openings b, desirably arranged vertically as shown, and there being desirably provided a series of vertical rows c, of openings b as shown. If desired, vertical slots may be substituted for the vertical rows of openings. As will be appreciated, the number, size, shape and arrangement of openings b is unimportant to the essence of this invention, it being contemplated that a single opening may be used and that where a plurality of openings are used they may be of various shapes, sizes, number and arrangement. Likewise, the opening or openings may be variouslyv located in the casing. l

Referring now more particularly to Figures 1 and 2, in which an electric blasting cap is illustrated, the cap casing w provided with vertical rows of'openings will contain .at its Vbottom a base charge e, which may comprise any suitable composition or mixture, as, for example, tetranitroaniline, picric acid, tetryl, etc. The base charge will be adjacent to but below the lowest of the openings b. Above the base charge the casing contains a top charge f, carried loosely within a capsule g formed of water soluble material as, for example, gelatin, etc., etc. The top charge may be composed of 'any well known composition or mixture, as, for example, ulminate-chlorate, diazodinitrophenol, lead azide, etc. The lcapsule g, which is open at its top, its tightly within the casing and acts as a closure for the openings b.

charge and the top charge may be contained in a capsule, as g, which may extend to the bottom of the casin or the capsule extending to the bottom o the casing may contain a single homogeneous detonatmg char e.

Re erring now more particularly to igures 3 and 4 in which a cap adapted to be fired by means of a fuse is shown, the casing which is' open at the top for the reception o a fuse contains a detonating charge of any suitable composition contained within a capge sule g of water soluble material and which lits in the lower portion of the casing and 1 acts as a closure for the openings b.

Iii` operation, -as will now be obvious, if a cap" ying the invention remains unired, for example in coal, when the coal is washed the capsule closing the apertures b will be dissolved sufficiently to open the openipgs or slots and the charge will be wash vout of the casing and away, all by the'wash waterwhich on dissolution of the capsule will have access to the inside of the lcasing and will wash out the charge therein throughv -the openings, which, as will be noted areopposite or adjacentv to the explosive cliar Nor charges.

As be understood, in order to render any cap safe, it is only neceary to wash out the charge which is sensitive to eat. Hence, the to charge which must be heat sensi- 40 tive, w ere use or the base charge,',if.heat

sensitive, or both ol' a homo eneous single char be loosel lo ed, or where tigh y com ressed be admixed with a water solub e material as, for example, potassium chlorate, sodium chlorate, or the lke,'in order to insure its removal by water on dissolution ofthe water soluble closure for the opening or openings in the casing.

Where the base charge is used with a top charge the former will not have suilicient heat sensitivit to present any hazard if it remains in, or example, coal and such charge may be tightly compressed and may remainV in the casing without damage so 56 lo as the top charge is removed.

will be appreciated, various modifications in the structures described above for illustrative purposes may be made without departing from this invention. Thus vari- 60 ous modifications may be made in connection with the t of this invention to various types of caps and, for example the openings as illustrated may be displace by various forms and arrangementsof openes ings thebody. of the casing or by an extend opening in the bottom thereof and the opening or openings may be closed by a patch or patches of water soluble material or by a sleeve in place of the capsule as described.

What I claim and desire to protect by Letters Patent is:

1. A blasting cap including in combination a casing provided with an opening, an explosive charge within the casing and a water soluble closure for said opening.

2. A blasting cap includin in combination a metallic casing provide .with an opening, an explosive charge within the casing' adjacent said opening and al water soluble closure for said opening.

3. A blasting cap including in combination a casing provided with an opening therein, a water soluble capsule within the casing and affording a closure for said opening and an explosive charge within the cas- 4. A blasting cap including in combination a casing lprovided with anfopening therein, a water lsoluble capsule within the casing and affording a closure for said opent ing and an explosive charge within the*` capsule.

5. A blasting cap includin in combination a casin provided wi a series of openings in t e side of the casing, a water soluble closure for said openings' and an explosive charge within the casing.

6. A blasting ca includingl in combination a casing provi ed with a series of openings arranged vertically in the side of 'said casing, a water soluble capsule within said casing and affording a closure for said openings and an explosive charge within said casing. y

7. A blasting ca including in combination a casing provi ed with a series of openings in vertical alignment, a water soluble capsule within the casing and aording a closure for said opening and an explosive charge within the casing.

8. A blasting cap including in combination a casing provided with a series of vertically extending slots, a water soluble capsule within the casing and affording a closure -for said opening and an explosive charge within the casing;

In testimony of whic invention, I have hereunto set my hand, at Wilmington, Delaware, on this 26th day of pril, 1932.

J EA PICCARD. 

